An electromagnetic-wave removal apparatus for electric heating mattresses is disclosed in Korean Patent No. 10-341280. According to the cited document, electric conducting wires spiraling in opposite directions relative to the direction of current are provided on a heating unit, thus attenuating the generation of electromagnetic waves. Further, electromagnetic waves which leak from the heating unit flow to ground through an electromagnetic-wave absorbing conductor having the heating unit therein. Thereby, the apparatus removes 95% or more of the electromagnetic waves generated in an electric heating mattress. As such, the apparatus has high efficiency.
As shown in FIG. 1, electromagnetic waves present in a residential space, such as a bedroom, are emitted from electrical appliances around a bed 6. The electrical appliances include lights 1 and 2, a television 5, a computer monitor 3, and a computer's main body 41 for example. When several electrical appliances are simultaneously used in a room, the density of electromagnetic waves in the room is increased, and thus the harmful influence exerted on the human body is increased.
In order to reduce the leakage of electromagnetic waves from the electric appliances during sleep, a method of installing an electric conductor in a blanket and grounding the electric conductor has been proposed, similar to a grounding electric heating mattress which transfers electromagnetic waves from a hot wire to the ground. The electric conductor, installed in the blanket to serve as the electromagnetic-wave absorbing device, moves released electromagnetic waves to the ground, thus shielding a sleeping person from the electromagnetic waves. Such a blanket is herein referred to as an electromagnetic-wave shielding blanket.
However, the blanket moves when in use. Thus, it is difficult to ground the blanket. Further, when a grounding apparatus of an electric heating mattress and a grounding apparatus of the electric blanket are independently installed, the environment surrounding the bed is disorderly. Therefore, in order to simplify the sleeping space while maintaining the function of shielding electromagnetic waves when using the electromagnetic-wave shielding blanket, it is desirable that the shielding blanket share a grounding apparatus with an electric heating mattress when an electric heating mattress is used.